Ansel   Adam's   has   said   that   the
techniques  of  the zone  system  should
become    "automatic"   so   that    the
photographer    can    concentrate    on
visualization.   Many  times,   however,
there  are  so  many  variables  in  the
mechanics,    that   concentration    on
anything else is difficult. Good records
are   also  indispensable,  both  as   a
learning tool, and in the darkroom.

This   is  a  program  that  will  allow
computation of accurate exposures in the
field.  It accomodates the zone  system.
It  will compute the effective  exposure
index  (EI) accounting for:  Filtration,
Zone  System expansion and  contraction,
Bellows
extension for normal lenses.

It also enters all data in a file called
LOG.DO  which may be printed upon return
from the field.
     
Here is a log example:

Wed 01/23/85 13:24:30 pax river hill's bridge
Zone III tree shadows  Zone VIII snow left bottom
Neg#> 1 Film >t-x ISO>  320  Adjusted EI>  23 
filter >K2+POL give N>-1 -10% processing
      
USE:

After  entering the program, a menu will
appear.  Menu  selection #1 pertains  to
the  film, #2 to the Exposure, #3 to the
Processing.
 
If  you  type <1>, the program will  ask
for  film  type, your normal  ISO  (ASA)
speed  for  that film and  the  negative
(film holder) number.
      
<2>  selection  will  ask  you  for  the
f-stop,  shutter  speed,  lens  fl,  and
filter. The f-stop and(or) shutter speed
will  likely  change after  you  compute
everything,  so  two trips through  this
menu  are probable. When you get to  the
filter  section,  you will be  presented
with  a filter menu, you can select more
than  one by going back to this  screen.
(From   the  main  menu).   For  bellows
extension,  you  are provided  with  two
methods,  subject/image size, or bellows
draw. Which method you use is up to you.
(These    formulas    only   work    for
symmetrical lenses)
     
<3>   is  the  entry  for  entering  the
expansion/contraction factors.

<4>  is a notation menu, here you record
the  subject,  the scene area  that  you
"place"  in zone III and the scene  area
that "falls" in zone VIII.
      
<6>NEW  simply  increments the  negative
number,  you  can  edit line 210  to  do
other  things like reset shutter  speed,
etc.

<7>  does  the  same thing as  <6>  plus
generate a  log entry.  At any time, you
can hit <enter> at the main menu and the
program  will compute the EI for the set
of  conditions that you have entered  up
to that point.
      
What  you  do is: set you meter  at  the
ISO,  do  your  place and  fall,  select
filters,  and let the program give you a
new  EI.  Set  that  EI  in  your  meter
(Instead   of   the  ISO),  and   expose
accordingly. 

If you change shutter speed, go back and
recompute,  (Reciprosity may have gotten
you!), get a new EI, etc.

I  am  more than willing to  answer  any
questions,  this is a favorite  subject!
     <billy b.> 70126,267